The invention relates to a prime mover for a vehicle, such as an engine or motor, having a plurality of cylinder chambers, a manifold and engine brake valves, which serve to connect the cylinder chambers to the manifold.
The invention further relates to a method for supplying a vehicle having a prime mover with compressed air, the prime mover having a plurality of cylinder chambers, a manifold and engine brake valves, which serve to connect the cylinder chambers to the manifold.
Modern vehicles, for example commercial vehicles and passenger vehicles in road transport or in rail transport on railroads, have many compressed air consumers, the compressed air requirement of which is usually met by a compressed air supply system, which includes a compressor. The air-consuming devices (or loads) may include a service brake and a pneumatic suspension, for example. The compressed air-generating compressor is usually driven directly by the prime mover, which is also used to propel the vehicle.
One disadvantage is that a compressor is actually needed in order to generate compressed air in the vehicle, but such a compressor takes up the overall space and increases the weight of the vehicle.
The object of the invention is to obviate the need, in normal operation, for a compressor with which to generate compressed air for the vehicle.
This object is achieved by a prime mover for a vehicle having a plurality of cylinder chambers, a manifold, and engine brake valves, which brake valves serve to connect the cylinder chambers to the manifold. A valve, which serves to connect the manifold to a feed line of a compressed air treatment system, is arranged on the manifold.
Advantageous embodiments of the invention are described herein.
The invention is based on the prime mover of generic type in that a valve, which serves to connect the manifold to a feed line of a compressed air treatment system, is arranged on the manifold. During engine braking, the prime mover of the vehicle is used to dissipate kinetic energy. At the same time, fuel injection into the cylinder chambers of the prime mover is interrupted in order to save fuel, the braking power being provided through compression work and the internal friction of the prime mover. The same applies during a coasting phase, the braking action of the prime mover here being undesirable, for which reason the air in the cylinder chambers is not compressed, but rather is pumped to and fro between the cylinder chambers via a manifold. By arranging a valve on the manifold it is possible, during engine braking or a coasting phase, to generate compressed air for the vehicle, which can be fed to the compressed air treatment system via the feed line.
The engine brake valves may usefully be individually actuated by an engine control unit. The individual actuation of the engine brake valves allows the specific connection of the individual cylinder chambers to the manifold during their respective compression strokes. The engine brake valves may advantageously be pilot-controlled by valve devices.
The invention further relates to a system for supplying a vehicle having a prime mover according to the invention with compressed air, and to a compressed air treatment system for treating the compressed air generated. Such a system is capable of providing compressed air for the individual consumers without a compressor.
In particular, a connection, from which untreated compressed air can be drawn, may be provided on the feed line. Consumers which only need compressed air of lower quality may be supplied with untreated compressed air from this connection, thereby relieving the compressed air treatment system.
The method of generic type is further developed in that the manifold is connected to a feed line of a compressed air treatment system by way of a valve. In this way the advantages and particular features of the prime mover according to the invention are also translated into a method.
This also applies to the especially preferred embodiments of the method according to the invention described below.
This method is usefully further developed in that during engine braking only the cylinder chamber in which compression work is currently being performed is connected to the manifold. Furthermore, during a coasting phase of the prime mover only the cylinder chamber in which compression work is currently being performed is connected to the manifold.
Some of the cylinder chambers can advantageously be connected to the manifold during their compression phase, whilst the remaining cylinder chambers are operated normally. In the absence of engine braking and also of any coasting phase, the prime mover can also be used to generate compressed air during a load phase. In this case, some of the cylinder chambers of the prime mover are used to generate compressed air, whilst the remaining cylinder chambers are used to drive the vehicle.
Preferably, no fuel is fed into the cylinder chambers which are connected to the manifold during the next compression phase. This measure serves to increase the quality of the compressed air generated by the prime mover, since the quantity of combustion residues and exhaust gases is reduced by a scavenging cycle that can be achieved in this way.
It is especially preferred that no fuel is fed into the cylinder chambers which are connected to the manifold during the next compression phase but one. If two scavenging cycles are performed in succession, the quality of the compressed air generated by the prime mover can be further improved.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.